http.go

/*
Copyright 2020 The Flux authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package testserver

import (
	"crypto/tls"
	"crypto/x509"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
)

// NewTempHTTPServer returns a HTTPServer with a newly created temp
// dir as the docroot.
func NewTempHTTPServer() (*HTTPServer, error) {
	tmpDir, err := os.MkdirTemp("", "http-test-")
	if err != nil {
		return nil, err
	}
	srv := NewHTTPServer(tmpDir)
	return srv, nil
}

// NewHTTPServer returns a HTTPServer with the given docroot set.
func NewHTTPServer(docroot string) *HTTPServer {
	root, err := filepath.Abs(docroot)
	if err != nil {
		panic(err)
	}
	return &HTTPServer{
		docroot: root,
	}
}

// HTTPServer is an HTTP/S server for testing purposes.
// It can serve files from the configured docroot and offers
// a lightweight middleware configuration option.
type HTTPServer struct {
	docroot    string
	middleware func(http.Handler) http.Handler
	server     *httptest.Server
}

// WithMiddleware configures the middleware of the HTTPServer, this can for
// example be used to configure Basic Auth credentials. It should be called
// before starting the server, or requires a stop/start cycle.
func (s *HTTPServer) WithMiddleware(m func(handler http.Handler) http.Handler) *HTTPServer {
	s.middleware = m
	return s
}

// Start starts the HTTPServer.
func (s *HTTPServer) Start() {
	s.server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		handler := http.FileServer(http.Dir(s.docroot))
		if s.middleware != nil {
			s.middleware(handler).ServeHTTP(w, r)
			return
		}
		handler.ServeHTTP(w, r)
	}))
}

// StartTLS starts the TLS HTTPServer with the given TLS configuration.
func (s *HTTPServer) StartTLS(cert, key, ca []byte, serverName string) error {
	s.server = httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		handler := http.FileServer(http.Dir(s.docroot))
		if s.middleware != nil {
			s.middleware(handler).ServeHTTP(w, r)
			return
		}
		handler.ServeHTTP(w, r)
	}))

	config := tls.Config{}

	keyPair, err := tls.X509KeyPair(cert, key)
	if err != nil {
		return err
	}
	config.Certificates = []tls.Certificate{keyPair}

	cp := x509.NewCertPool()
	cp.AppendCertsFromPEM(ca)
	config.RootCAs = cp

	config.ServerName = serverName
	s.server.TLS = &config

	s.server.StartTLS()
	return nil
}

// Stop stops the HTTPServer, if started.
func (s *HTTPServer) Stop() {
	if s.server != nil {
		s.server.Close()
	}
}

// Root returns the configured docroot of the HTTPServer.
func (s *HTTPServer) Root() string {
	return s.docroot
}

// URL returns the address the HTTPServer is listening at,
// if started.
func (s *HTTPServer) URL() string {
	if s.server != nil {
		return s.server.URL
	}
	return ""
}